Energy Cost

Exergy Cost

Boiler

$C_{n,b}=\frac{c_f}{{\eta }_{g}HHV}$

$C_{nx,b}=\frac{c_f}{{\phi }_g{\psi }_{b}HHV}$

Diesel Generator

$C_{n,g}=\frac{c_f}{{\eta }_{g}HHV}$

$C_{nx,b}=\frac{c_f}{{\phi }_g{\psi }_{g}HHV}$

Mean Electricity Output

${\overline{C}}_{n,e}=\frac{C_m+W_{e,m}+C_{n,g}x{Q}_g}{W_{e,m}+{\eta }_g{Q}_g}$

${\overline{C}}_{x,e}=\frac{C_m+W_{e,m}+C_{n,g}x\phi Q_g}{W_{e,m}+{\psi }_g\phi Q_g}$

Overall Mean Energy Unit Cost

${\overline{C}}_n=\frac{C_m+W_{e,m}+C_{n,g}x{Q}_g+C_{n,b}x{Q}_{i,b}}{W_{e,m}+{\eta }_g{Q}_g+{\eta }_b{Q}_{i,b}}$

${\overline{C}}_x=\frac{C_m+W_{e,m}+C_{n,g}x\phi Q_g+C_{x,b}x\phi Q_{i,b}}{W_{e,m}+{\psi }_g\phi Q_g}$

Energy Cost of Production (₦/tonne)

overall mean energy unit cost (₦/GJ) × embodied energy intensity (GJ/tonne)